RAJASTHAN PMT Rajasthan - PMT Solved Paper-2009

  • question_answer
    The sun radiates energy in all directions. The average radiation received on the earth surface from the sun per second is \[1.4\,kW/{{m}^{3}}\]. The average distance between sun and earth is \[1.5\times {{10}^{11}}m\]. The mass lost by the sun per day

    A)  \[4.4\,\times {{10}^{10}}kg\]    

    B)  \[7.6\,\times {{10}^{14}}kg\]

    C)  \[3.8\times {{10}^{11}}kg\]     

    D)         \[3.8\times {{10}^{14}}kg\]

    Correct Answer: B

    Solution :

    Energy emitted per second from the sun                 \[=1.4\times {{10}^{3}}\times 4\pi {{r}^{2}}\]                 \[=1.4\times {{10}^{3}}\times 4\pi \times {{(1.5\times {{10}^{11}})}^{2}}\] \[\therefore \]Energy emitted per day from the sun, \[=1.4\times {{10}^{3}}\times 4\times \frac{22}{7}\times 2.25\times {{10}^{22}}\times 24\times 3600\] \[=8\times 22\times 225\times 864\times {{10}^{24}}\] From Einsteins mass-energy relation,                 \[E=m{{c}^{2}}\] \[\therefore \]  \[m=\frac{E}{{{c}^{2}}}\]                     \[=\frac{8\times 22\times 225\times 664\times {{10}^{24}}}{{{(3\times {{10}^{8}})}^{2}}}\]                     \[=7.6\times {{10}^{14}}kg\]


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